The present invention relates generally to heaters and more particularly to heaters having apparatus attached thereto for introducing water into such heater for carrying more heat out the outlet thereof for drying and curing purposes.
In the art of curing concrete products, a common type of heater used is a boiler sending steam heat to a heat distributing network underneath the concrete to be cured. The disadvantages of this type of a heating system were discussed in U.S. Pat. No. 4,147,323 to Welden. In that patent, a linear type of heater and heat distributing network was disclosed of a type wherein the products of combustion are distributed with the air blown through the heater rather than allowing this heat to be wasted by going up a stack. This type of a linear heater can be used for anything that can tolerate the by-products of combustion; for example, in curing cement block, concrete pipe, pre-stressed concrete structures, etc.
While it has been discovered that this type of linear heater discussed above is much more efficient than prior art heat systems, the efficiency of such a heater, it has been found by the present inventor, can be increased considerably by introducing water to the air passing through such heater so that the air can deliver much more heat for each amount of air delivered.
In the development of trying to produce a linear heater and introducing steam thereto, private experiments by the present inventor were conducted. First of all, it was determined that if the heating chamber was vertically oriented that the water passed straight out the bottom before being completely vaporized, and slugs of water went out the outlet pipe and thereby interferred with the curing of the concrete product.
In an attempt to overcome this problem, in still further private experiments by the inventor, a horizontally disposed heating chamber was experimentally used and it was discovered that water tended to accumulate in the bottom of such heating chamber and that surges of water pulsated out of the outlet from time to time which was, again, undesirable since the concrete would not cure properly under such circumstances.
Accordingly, it was established by these experiments that there is a need for an apparatus for introducing water into the heating chamber of such a heat furnace long enough to be sure that it is vaporized, and allowing water to always be present in the heating chamber to be sure that the heater is operating at optimum efficiency, while at the same time preventing surges of water out of the outlet of such heating chamber.